Nesting grid structure for a geographic referencing system and method of creating and using the same

ABSTRACT

A nested grid structure of a geographical referencing system includes one or more regional grids generally centered on one or more respective grid origins, each regional grid including a plurality of cells. One or more local cities are located at least partially within the one or more regional grids. One or more local city grids, each including a plurality of cells, are generally centered on one or more respective local city origins of the one or more local cities. At least some of the plurality of cells of the one or more local city grids directly overlap and coincide with at least some of the plurality of cells of the one or more regional grids to form a nested grid structure.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 09/645,814, filed Aug. 24, 2000, now U.S. Pat. No. 6,295,502, which is a continuation of U.S. patent application Ser. No. 09/257,462, filed Feb. 25, 1999, now U.S. Pat. No. 6,202,023, which is a continuation-in-part of U.S. patent application Ser. No. 09/188,153, filed Nov. 4, 1998, now U.S. Pat. No. 6,047,236, which is a continuation of U.S. patent application Ser. No. 08/701,586, filed Aug. 22, 1996, now U.S. Pat. No. 5,839,088. The above referenced patent and applications are incorporated herein by reference as if set forth in full.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates, in general, to grid structures used for geographic referencing systems, and, in particular, to nesting grid structures for geographic referencing systems.

2. Related Art

U.S. Pat. No. 5,839,088 describes a geographic location referencing system entitled the World Geographic Referencing System (“WGRS”). The WGRS was developed by Go2 Systems, Inc. (“Go2”) of Irvine, Calif., the same assignee as the present invention. The WGRS has an addressing scheme that is determined using a number of pre-defined grids. An address for a geographical location may be determined by determining a grid corresponding to the geographical location, subdividing a cell of the grid into as many levels of hierarchically arranged sub-cells as necessary to obtain a desired addressing precision, associating each sub-cell with a sub-cell code, identifying each sub-cell with a hierarchical arrangement of codes, and appending to the name of the grid a hierarchical arrangement of codes corresponding to the geographical location. The inventors of the present invention recognized it is additionally desirable in a geographic location referencing system to nest regional grids and local city grids so that a geographical location may addressed with respect to a local city grid and/or a regional grid. Navigation with respect to local city grid addresses is desirable because a local frame of reference generally has more meaning to users, especially users that do most of their navigation in a local area or city. Navigation with respect to a regional grid address may be more desirable for users that travel more outside of their local area or city. Correlating two partially overlapping grids so that certain areal and point references are congruent at higher levels of precision provides significant advantages.

SUMMARY OF THE INVENTION

Accordingly, an aspect of the present invention involves the recognition that it would be desirable to nest local city grids with regional or district grids so that a geographical location may be identified with respect to a regional grid and/or one or more local city grids. It is anticipated that for most users of the WGRS described herein, the majority of use will be on a local level. Being able to identify a geographical location with reference to a local city grid localizes the geographic referencing system, making the geographic referencing system more meaningful to the user.

Another aspect of the invention involves a nested grid structure of a geographical referencing system. The nested grid structure includes one or more regional grids generally centered on one or more respective grid origins, each regional grid including a plurality of cells. One or more local cities are located at least partially within the one or more regional grids. One or more local city grids, each including a plurality of cells, are generally centered on one or more respective local city origins of the one or more local cities. At least some of the plurality of cells of the one or more local city grids directly overlap and coincide with at least some of the plurality of cells of the one or more regional grids to form a nested grid structure.

An additional aspect of the invention involves a method of creating a nested grid structure for a geographical referencing system. The method includes determining a regional origin for a regional; centering a regional grid for the region generally on the regional origin, the regional grid including a plurality of cells; determining a local city origin for a local city located at least partially within the regional grid; and positioning a local city grid including a plurality of cells so that the local city grid is generally centered on the local city origin and at least some of the plurality of cells of the local city grid directly overlap and coincide with at least some of the plurality of cells of the regional grid to form a nested grid structure.

A further aspect of the invention involves a method of addressing a geographical location using a local city grid. The method includes providing a geographical location; determining a local city grid corresponding to the geographical location, the local city grid having a plurality of grid cells, a local city grid origin having global coordinates defined in accordance with a known global referencing system, and a local city grid name; subdividing a cell corresponding to the geographical location into as many levels of hierarchically arranged sub-cells as necessary to obtain a desired addressing precision; associating each sub-cell with a sub-cell code; identifying each sub-cell with a hierarchical arrangement of codes; and addressing the geographical location with an address formed by appending to the name of the local city grid a hierarchical arrangement of codes corresponding to the geographical location.

A still further aspect of the invention involves a method of addressing a geographical location within overlapping geographical areas of a regional grid and a local city grid of a geographical referencing system. The method includes providing a first address of a geographical location in a first geographical area, the first address comprising a hierarchical arrangement of codes of a first pre-defined grid corresponding to the first geographical area appended to the name of the first grid, the first grid being either a regional grid or a local city grid; determining a second pre-defined grid which corresponds to a second geographical area, the second geographical area having a portion which overlaps at least in part the first geographical area, the geographical location being within the overlapping portion, the second pre-defined grid being the opposite of the first predefined grid, either a regional grid or a local city grid; determining a hierarchical arrangement of codes of the second grid corresponding to the geographical location; and appending the hierarchical arrangement of codes of the second grid corresponding to the geographical location to the name of the second grid to form a second address of the geographical location.

A yet further aspect of the invention involves a method of addressing a geographical location using a nested grid structure of a geographic referencing system, the nested grid structure including one or more local city grids nested with one or more regional grids. The method includes providing a geographic location; determining a grid which corresponds to the geographical location, the grid including at least one of the one or more local city grids and the one or more regional grids; determining a hierarchical arrangement of codes of the grid corresponding to the geographical location; and appending the hierarchical arrangement of codes of the grid corresponding to the geographical location to the name of the grid to form an address of the geographical location. In a preferred implementation of this method, the type of address generated, local or regional, may depend on user preference.

Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 shows two overlapping districts, each with a reference point and a grid system.

FIG. 2 shows a single cell of FIG. 1 with hierarchical gridding to increase the addressing resolution.

FIG. 3 is a functional diagram of a preferred embodiment of the invention.

FIG. 4 shows how proprietary locational names are compiled and distributed.

FIG. 5 is a diagram of a navigational system incorporating one or more aspects of the subject invention.

FIGS. 6 and 7 show the use of PLAs and ULAs in a specific geographical context.

FIGS. 8a-8 b, 9, 10 a-10 c, 11 are examples of specific files used in one implementation of the subject invention.

FIGS. 12a-12 c are examples of screen outputs used in one implementation of the subject invention.

FIG. 13 depicts an operational environment of the automatic location aspect of the present according to a preferred embodiment.

FIG. 14 is a block diagram depicting details of the portable-computing device in accordance with the subject invention.

FIG. 15 is a block diagram depicting functional components of an application program or program(s) running on the portable-computing device in accordance with an embodiment of the present invention.

FIG. 16 is a flowchart that generally describes an overall process in accordance with an embodiment of the present invention.

FIG. 17 is a flowchart depicting a process that can be used to implement a portion of the Go2 Application program according to an embodiment of the present invention.

FIG. 18 is a flowchart depicting a process that can be used to implement a process performed by the primary server upon connection with the client according to an embodiment of the present invention.

FIG. 19 is a flowchart and block diagram useful for describing the interaction and processing between the client, the primary server and an enhanced server according to an embodiment of the present invention.

FIG. 20 is a flow chart depicting a method that can be used to implement the automatic location data collection feature according to a preferred embodiment of the present invention.

FIG. 21 depicts an example of a site plan that can be used to implement an embodiment of the present invention.

FIG. 22 is a district grid constructed in accordance with an embodiment of the invention.

FIG. 23 is an embodiment of a sub-grid of the district grid illustrated in FIG. 22.

FIG. 24 is a nested district and local city grid structure constructed in accordance with an embodiment of the invention.

FIG. 25 is a flowchart of an embodiment of a method of addressing a geographical location using a local city grid such as that illustrated in FIG. 24.

FIG. 26 is a flowchart of an embodiment of a method of addressing a geographical location within overlapping geographical areas of a district grid and a local city grid of a geographical referencing system.

FIG. 27 is a block diagram of a computer useful for implementing components of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention involves a nesting grid structure for a geographic referencing system and a method of creating and using the same. In a preferred implementation, the nesting grid structure is used in conjunction with the World Geographic Referencing System (“WGRS”). A discussion of the WGRS is in U.S. Pat. Nos. 5,839,088, 6,047,236, 6,202,023, and 6,223,122, all assigned to Go2, and is generally set forth below in sections I-VI below. Section I describes an exemplary process for creating the WGRS. Section II describes the WGRS in use. Section III describes details and examples of WGRS Implementation. Section IV describes several exemplary applications of the WGRS. Section V describes some examples of software implementation related to the WGRS. Section VI describes an internet-based automatic location referencing system using the WGRS. The final section, Section VII, describes a nesting grid structure for a geographic referencing system and an exemplary method of creating and using the same.

I. World Geographic Referencing System

An embodiment of the WGRS or geographical referencing system will now be discussed. The WGRS allows a point of interest (“POI”) within an arbitrary geographic area to be uniquely identified with a unique, domain-name like hierarchical geographical referencing address or locational address, and the locational address to be related to other known global referencing systems.

A. Creation of the World Geographic Referencing System

The WGRS is created by dividing a geographic area into several districts. The districts may be of the same or differing size and shape, and may contain a particular identifying feature. For example, the geographic area of the United States may be subdivided into numerous districts, which may be strategically located, sized, and named with reference to cities or other geographic or political features in order to associate the districts with such features. Advantageously, such districts are chosen relative to cities and other well-known landmarks and it is therefore convenient to name each district according to the city or landmark about which the district is located. In fact, each city may have a reference point, allowing local locations to be addressed relative to the local city. Preferably, the districts are square and all of the same size, e.g., 100 km×100 km, with overlapping portions of districts nested with each other. However, in alternative embodiments, sparsely populated areas may have larger districts, and densely populated areas may have smaller districts. The districts may also be quasi-rectangular, following latitude and longitude lines. In more densely populated areas, it is possible that a particular location will be within the boundaries of two or more districts. In addition, user-defined districts, reference points, and grid sizes are possible. For example, a search and rescue operation may establish a reference point and grid size convenient for a particular search area, or a group of hikers may choose a reference point and grid size appropriate for a particular outing.

After the districts have been selected and named, a reference point is chosen for each district, and a grid system placed relative to the reference point. Advantageously, the grid system is referenced north. Referring to FIG. 1, a first district 1 and a second district 3 are defined relative to major cities 4 and 6 respectively. In this example, major city 4 in the first district 1 will be named CITYONE and the major city 6 in the second district 3 will be named CITYTWO. One or both of these cities 4, 6 could be local cities. For convenience, the first district 1 will be named CTY1, referring to the major city within that district's borders, and the second district will be named CTY2, referring to the major city within that district's borders. Reference point 5 is selected as the reference point for CTY1, and reference point 7 is selected as the reference point for CTY2. The reference point will not necessarily be located proximate to the feature used as the name for the district. Each reference point 5 and 7 has a known address within a global referencing system such as World Geodetic Systems (WGS). Association with a global system offers at least three important functions: first, local addresses may be easily converted to global addresses and vice-versa; second, inter-district relationships are established; and third, easy integration with known navigational systems is provided. Thus, an easy to use district-level addressing system retains the advantages of a global system without attaching complexity.

As can be seen in FIG. 1, the grid system about each reference point 5 and 7 creates cells 9 in each district. Each of these cells 9 is identified with a cell code, which advantageously is a two character number. The grid system is better understood when discussed in conjunction with an exemplary target POI location such as POI location 19 within the grid system. For example, the target POI location 19, which is in cell 11, can now be identified by a domain-name like hierarchical geographical referencing address or universal locational address (“ULA”) referring to its district and cell code, e.g., CTY2-11. For example, if CTY2 is Los Angeles, the hierarchical address for the POI location 19 may read US.CA.LA.11, where “US” indicates that POI location 19 is in the United States, “CA” further indicates the POI location 19 is in California, “LA” further indicates the POI location 19 is in the Los Angeles grid, and “11” further indicates that the POI location is in cell code 11 of the Los Angeles grid. Of course, portions of the address such as “US.CA” may be removed from the address if this is self-evident or always understood so that the POI location 19 may be understood by the address LA.11. Although the address CTY2-11 or LA.11 lacks the resolution to identify a particular feature, such as a house, the address may be enough resolution to locate a lake or park. As will be discussed in more detail below, the POI location 19 can be addressed by further hierarchical sub-cell or sub-grid addressing to identify a particular feature, e.g., the POI location may be a house that may be specifically identified by the hierarchical address U.S.CA.LA.11.17.18.12. Thus, the hierarchical nature of the WGRS and the domain-name like addressing system based on the same allows multi-precision searches to be performed. The issue of increased resolution is discussed below.

Also, it is likely that there will be an overlap area 13 that is formed at the intersection of districts. Within this overlap area 13, any POI can be identified by reference to any district within which it is located. Thus, a target location 8 in the overlap area 13 can be identified by either association with the CTY1 or CTY2 districts, or any other district within which it is located. In the preferred embodiment, a locational system can provide a locational address relative to any reference point or district by simply toggling between reference points. Although the grids 1, 3 are shown at an angle relative to one another, the grids 1,3 are preferably aligned with each other and overlapping cells 9 of relative grids such as those shown in overlap area 13 are nested so that they directly overlap or coincide with each other.

As discussed above, a district name and cell code may not give sufficient resolution to locate specific locations such as a house or business. To increase resolution, a hierarchical grid is applied to each cell 9 of FIG. 1. For example, cell 11 is shown in FIG. 2 with a sub-grid applied, producing sub-cells 15. Each of these sub-cells can be identified with a sub-grid code. Moreover, the sub-cells can be further subdivided to increase resolution. Here, sub-cell 17 is further subdivided. As can be seen in the figure, the target location 19 is within the sub—sub cell 18. Thus, to more definitively identify the target location 19, an ULA is formed from the highest resolution sub-cell defined and each of its parent cells. The locational address is formed by appending to the district name each sub-cell code in hierarchical progression, moving from lower resolution to more resolution. In the Los Angeles example here, the target location 19 would have a locational address of CTY2-11-17-18 or LA.11.17.18. Based on the size of the district, if this does not give the necessary resolution to properly locate the target location 19, then additional levels of gridding hierarchy can be added. Although, in this example, each cell was randomly named with a unique numerical code, it should be appreciated that a consistent Cartesian coordinate system can also be used, with each cell defined by an (X, Y) coordinate pair. Preferably, each cell is identified by an easting cell designator or X axis coordinate, paired with a northing cell designator or Y axis coordinate, with the easting cell designator as first number or letter in the pair and the northing cell designator as the second number or letter in the pair. Those skilled in the art will recognize several other alternative ways to define a grid system, some of which are described further below.

Advantageously, a city or landmark area will be named with a specific abbreviated name for purposes of navigating to and around that city or landmark area. That abbreviated name may also serve as the name of the defined district located about that city. Preferably, the grid established for each city or landmark area is preferably a constant 10×10 grid, 100×100 km, or 10,000 sq. km. and overlapping cells from overlapping city or landmark areas are nested so that cells directly overlap or coincide with each other. In an alternative embodiment, depending on the size of the city and various geographic, political, and other features relating to the city or region, the district for that particular city may be pre-defined with a particular grid size, although the system may allow altering the grid size for particular purposes. If, in the preceding example, the defined grid size for CTY2 is approximately 30 by 30 nautical miles, identifying two hierarchical grids produces a resolution of about 500 meters, which is sufficient for locating structures in open areas or large targets such as lakes or parks. By adding a third and fourth hierarchical grid, a resolution of about 5 meters is achieved, and by adding a fifth hierarchical grid, a resolution of about 0.5 meters is achieved. By adjusting the number of grids, then, the resolution of the resulting locational address is changed to meet the requirements of the particular area or user. Advantageously, similar to a domain name for a web address, each level of the hierarchical address is separated by a decimal point. Thus, an address may appear as “DISTRICT.12.34.56.78”. Those skilled in the art will recognize several alternatives to this approach.

B. Alpha Codes

In a preferred embodiment, the above coding technique is extended to include standard alpha codes representing objects such as suites, floors, rows, columns, altitude, etc. These alpha codes are advantageously appended to the above code as they logically represent the highest resolution component. Thus, for example, suppose the above locational address of CTY2-11-17-18 represents an office building, then the address of CTY2-11-17-18-S101 represents suite 101 in the office building. Likewise, the address CTY2-11-17-18-F2 represents the second floor of the office building. In another example, the address CTY-11-17-18-R101-RW12-C22 represents row 12 column 22 in room 101 of the office building. This can represent an exact location within a particular rack in a warehouse, for example. In another example, the address CTY2-11-17-18-HS2200 represents a height of 2200 feet above sea level.

As can be appreciated by those skilled in the relevant art(s), this technique can be extended as much as required. Typically, a standard set of codes is defined for each specific implementation of the present invention. An example of such a set of codes that can be used in an embodiment of the present invention is shown below in Table 1.

TABLE 1 Example set of alpha codes and their definitions. Alpha Code Definition AL AISLE A APARTMENT AD ADDRESS BX BOX B BIN BY BAY C COLUMN CS CASE D DOOR DP DEPTH DY DAY EL ELEVATOR EN ENTRY E ELEVATION ES ESCALATOR F FLOOR FD FIELD GR GARAGE G GATE H HEIGHT HE HEIGHT ABOVE ELLIPSOID HG HEIGHT ABOVE GEOID HO HEIGHT ORTHOMETRIC HS HEIGHT ABOVE SEA LEVEL HT HEIGHT ABOVE TOPOGRAPHICAL SURFACE HU HOUSE LK LOCKER L LEVEL NO NUMBER PO P.O. BOX PH PHONE PN, PIN PIN # R ROOM RW ROW RD ROAD ST STREET S SUITE SC SECURITY CODE SN SECTION SE SEAT T TIME TR TRAM TN TRAIN TK TRACK U UNIT X INTERSECTION Z ZIPCODE

C. Proprietary Location Address

The second way a point of interest may be designated in the subject invention, in addition to its ULA, is with a proprietary locational address (“PLA”). Referring to FIG. 4, the first step in using a PLA is to identify the feature and select a name 51. A PLA is a name chosen to identify a physical structure or location. The name can be chosen by the operator of a locational service, as in the case of naming national monuments, or the name can be chosen by individual or corporate users of the locational service. Individuals may even want to identify their homes using their own names. Thus, a Ms. Mary Smith may name her house MARY.SMITH.HOUSE, for example. Thus, when Ms. Smith wants to direct someone using a locational service to her house, she identifies her location using MARY.SMITH.HOUSE, rather than a street address or other locational referencing system. A corporation, too, may desire to allow customers to locate it using a common name rather than a less personal addressing system. For example, a nationwide enterprise such as McDonalds® with many locations may choose a PLA that is associated with its tradename or product or otherwise allows users to easily remember and associate the establishments PLA. Abbreviations are useful as it keeps user input to a minimum, increasing safety, reliability, and convenience. Since the nation-wide enterprise may have many locations in a single metropolitan area, each may be identified by appending to the enterprise's PLA a unique identifier to identify specific branch offices or affiliates. Wildcard searching is also provided, allowing several locations of the known nation-wide enterprise to be found for a particular geographic area.

The capture of positional information for a certain name will now be described. Referring to FIG. 4, as indicated by identifying numeral 55, positional information could be entered manually, by, for example, inputting the ULA or coordinates of the location from a known mapping system. Alternatively, as indicated by identifying numeral 57, the positional information may be read electronically using a system such as the GPS. Referring again to FIG. 4, the name 51 and positional information 53 are associated. The district in which the location is identified is determined by comparing the positional information 53 to stored district locational information 54. Once the district is identified, the name is checked against other reserved names in the district to assure the selected name is unique. If the name is unique, it is placed in a district data file 63. As can be seen from the discussion above, uniqueness of the name need only be checked at the district level. Consequently, the same name can be present in different districts. The name must be unique at the district level as the district name usually becomes part of the PLA. For example, the nation-wide enterprise location in district CTY1 could have a full PLA of CTY1-TRADENAME. If the owner of a name desires to more widely reserve a name, each district will be checked individually.

Once a PLA is approved for an individual, corporation, or other entity, the PLA may be placed in promotional material such as advertisements, coupons, billboards, or other means of communication. By providing a PLA that describes a feature, a particular location may be quickly identified and readily found.

Once cleared for conflicts, the name, positional information, and any other useful information are stored in a central repository location. This storage may be sortable and selectively downloadable by users of locational systems. For example, the central repository may be accessible via the Internet. In such a case, a user 75 would make a request for information 71 concerning future travel, such as the ULAs or PLAs of specific desired waypoints of a trip. The information in the central repository 65 is selected and sorted, and the travel data 73 is received by the user, creating a travel profile. To ease the data selection process, the central repository may store preferences for the user. After receiving the travel profile, the user places the travel data 73 into a navigational unit 77, augmenting information 79 already locally present in the navigational unit 77. The user 75 may then use the travel data 73, including PLAs and ULAs, to assist in navigating.

II. Method of Using World Geographic Referencing System

The WGRS will now be described in use. Initially, the process for determining a WGRS address will be discussed, followed by the process for converting between WGS and WGRS addresses.

A. WGRS Address Determination

Use of an ULA in a navigation system and an exemplary method for WGRS address determination will now be described. Referring to FIG. 3, district file 31 is maintained correlating district names and locational information relating to those districts. Regional information 33, that may be manually entered (as indicated by reference numeral 21) by a user, may also be maintained. This regional information 33 is used by the system to reduce the amount of information a user must enter to identify a particular location. The regional information may, for example, be a map code or distinct name identifying the general area covered by the map. Alternatively, it may be the name of a district having a pre-defined grid. After the map code or district name is inputted as regional information, the system now assumes that any future user inputs are within the geographical area defined by the regional information, thus reducing the complexity of inputting future addresses referenced on that map. Also, positional information 35 of a current location may be input manually (reference numeral 23) or electronically (reference numeral 25) for the same purpose. By knowing the present location, the system may assume that any subsequent address input by the user is within the same geographical area as the present location. Again, the purpose and effect is to reduce the complexity of inputting locational addresses.

The user may also electronically (reference numeral 29), or manually (reference numeral 27) input a specific address 37 to the system. By comparing the regional information 33 and positional information 35 of the current location with the stored district information 31, a general address can be formed. This general address will contain the district name plus any cell and sub-cell codes that are more general than the most general code in the specific address. The resolution detector 43 attempts to determine how much resolution is represented by the specific address 37 input by the user, and in conjunction with the comparison 41 function, creates a general address 45 with the correct level of resolution. Again, it is assumed that any subsequent addresses input by the user are within the same geographical area defined by this general address.

Once the resolution of the specific information 37 is determined, the specific information 37 is passed on to become a specific address 47. This specific address 47 is appended to the general address 45 formed above to form the final locational address 49. The locational address 49 is then used by the navigational system to assist in navigation. Additionally, an emergency mode may be provided in which a present location is automatically referenced to any reasonably close PLA or other known location.

B. WGRS Address and WGS Address Conversion

A relationship with World Geodetic System 1984 (“WGS-84”), allowing locational addresses to be converted to other global addressing systems, is also provided. A further description of the district grid is needed to understand this relationship. Each district has a reference point, with the reference point being the approximate center of the city used in naming the district. A grid is placed in relation to the reference point such that the origin of the grid is aligned with the nearest intersection of latitude and longitude lines corresponding to the largest grid resolution in the district. Since the reference point has a known WGS-84 address, by knowing the origin offset, the district rotation, and the district scale, every WGRS ULA can be translated into a WGS-84 address, and from there into nearly all locational reference systems. Conversely, every WGS-84 address may be translated into one or more WGRS ULAs. The translation is simplified in the subject invention as the district grid system is generally aligned to the WGS-84 latitude/longitude grid.

C. Use of the WGRS in a Navigation System

The aspects of the WGRS may be performed locally such as in a mobile navigation system or remotely such as at a remote serve. With reference to FIG. 5, aspects of the WGRS will described in conjunction with a mobile navigation system. An exemplary navigational system comprises a GPS receiver 100, an input device 101 such as a keypad or the like, a processor 102, a storage device 103 such as RAM or ROM, and an output device 106 such as a display. The GPS receiver 100, input device 101, storage device 103, and output device 106 are all coupled to the processor 102 as shown. An application program 104 executes in the processor to perform various tasks. Optionally, a look-up-table (hereinafter “LUT”) 105 is provided in the storage device 103.

The application program in a conventional navigational apparatus typically interfaces with and directs the aforementioned elements to perform the following tasks:

1. Displays the latitude and longitude (hereinafter “lat/lon”) of the unit—First, the GPS receiver receives signals from the GPS satellite constellation, and calculates the location of the unit (in terms of lat/lon) using these signals. The lat/lon coordinates of the unit are then displayed on the output device 106.

2. Displays velocity and bearing—if the unit is moving, the processor determines the location of this unit at selected time intervals, and based thereon, determines velocity and bearing. Once determined, this information is displayed on the output device 106.

3. Allows for the selection of waypoints—In one approach, a user inputs waypoints through input device 101 in terms of lat/lon coordinates. In another approach, common in the aviation community, a look-up-table or the like, identified with numeral 105 in FIG. 5, is provided, correlating pre-determined waypoints with lat/lon coordinates. A capability for searching through the database and selecting particular waypoints is also provided in this approach.

4. Displays distance and bearing from selected waypoints—once the waypoints have been determined, the distance (assuming straight line) and bearing from these waypoints is determined and displayed.

Additional components of the system which are added by the subject invention include context buffer 108; front-end interface (hereinafter “FEI”) 107; PLA database 110; and a database(s) 109 of grid definitions.

A critical function of the front-end-interface is to convert ULAs and PLAs into lat/lon coordinates. Consequently, a user can input waypoints in terms of ULAs or PLAs, and the FEI will convert the same to lat/lon coordinates for use by the unit in determining a directional and/or distance indicator (such as distance and bearing) from the waypoints. Additionally, positional information defined in terms of lat/lon coordinates can be displayed in terms of one or more ULAs of the subject invention. The FEI also includes various searching capabilities to allow a user to search through the PLA database 110 for particular waypoints or waypoints with particular characteristics.

The function of the context buffer 108 is to define the current district and grid in which grid addresses are assumed to be defined.

The grid definition file(s) 109 specifies all the grids which have been defined to date. For each grid, all the parameters necessary to define the gird are stored. Such information includes the lat/lon coordinates of the reference point of the grid, the dimensions of the grid, and the rotation and scaling of the grid cells. Thus, all the information needed to convert between a grid address within the grid and lat/lon coordinates is provided.

The PLA file 110 is a file which for each district correlates each PLA which is unique to and has been reserved for use in the district with its corresponding grid address.

The navigational system described above may be mounted in a vehicle or contained in a portable device, for example. Additionally, the navigational system may stand alone or may be integrated into existing devices, such as portable phones. Further, the subject invention may be incorporated into a general computational device such as a microprocessor. Since the physical manifestation of the navigational system is so flexible, there are numerous foreseeable applications.

III. Details and Examples of WGRS Implementation

The examples set forth below describe various details of various implementations of the WGRS. Examples 1, 1A, 2, and 3 demonstrate specific implementations of one embodiment of the invention: Example 1 demonstrates the use of Hierarchical Identifiers for districts which are correlated with Country, State/Province, and City districts along with PLAs and a purely numeric ULA grid referencing system based upon a district grid size of approximately 100 kilometers from north to south or approximately 100 miles (185 kilometers) north to south. Example 1A demonstrates an alternative means that can be used to implement the city grid based on the Transverse Mercator projection system. Example 2 demonstrates the use of the Hierarchical Identifiers described in Example 1 along with an alternating alpha-numeric ULA grid referencing system. Example 3 demonstrates the use of a smaller City Grid and the resulting higher precision at various grid levels.

A. EXAMPLE 1 Hierarchical Identifiers for Country, State/Province, City

The example assumes the existence of higher levels of hierarchical codes for identifying countries, states/provinces, and cities. The top level codes can be used, implied by context, or specifically ignored by the use of dots (periods) to make it clear how many codes have been omitted. A code of ‘US.CA.LA’ might be represented as ‘LA’, ‘ . . . LA’, or by ‘CA.LA’, depending on the geographic context or the need for clarity.

In all cases, upper level codes are dropped when the geographic context is clear, to prefix with dots (periods) when necessary to insure clarity, and to append lower levels to add precision.

Country Codes

Top level: two alpha character mnemonic (possibly based on Internet domain codes).

Examples

United States=US

Australia=AU

Canada=CA

State/Province Codes

Second level: two character mnemonics (advantageously based on US postal codes within the US).

Examples

California=CA

New York=NY

City Codes

Third level: two or three alpha character mnemonics from city name unique within each state.

Examples

Carbondale=CAR

Hartford=HAR

Los Angeles=LA

New York City=NYC

Proprietary Codes

Fourth level; one or more alpha or numeric characters which are unique within a specific grid or map with a unique map code

Examples

MACD, DISNEY, EXXON, etc.

An example of a use of a PLA might be US.GA.ALB.MACD to refer to a MacDonalds in Albany, Ga.; US.GA.ALB.MACD* to refer to the closest(s) one in Albany, Ga.; or MACD* to refer to the closest(s) ones in any city.

The code . . . ALB.MACD* could refer to either the nearest MacDonalds in Albany Ga. or Albany N.Y. and context. .NY.ALB.MACD* would resolve the context.

City Grid

This optional code is at a fourth or fifth level; identified by the first use of a pair of numeric characters in the city grid code. The city grid system requires an approximate city centroid described in a locational reference system such as geodetic latitude and longitude and the meaning of each pair of grid designators. The city grid origin is defined at the south-west coordinate system intersection value corresponding to exact values of the largest grid resolution precision that is defined in the city grid, placing the district centroid within the center grid cell of the system.

In the nominal city grid system, the grid cells are orthogonal to the defining coordinate system; however, rotations and scale parameters can be used to re-define the relationship between the city grid and the reference frame. False easting and false northing offsets (translations) are normally used to avoid negative numbering or to allow convenient ordering of alphanumeric designators.

Conversion from the defining reference frame (e.g., lat/lon) to city grid designators (i.e., ULAs) is accomplished by computing conversion constants based on the initial reference frame and the specific city grid definitions. When geographic context has already been established, grid designators are computed with respect to the currently selected district. When no district has been selected as the preferred one, the nearest district centroid is used as the basis for the grid designators. Conversion from city grid to coordinates in the defining system is accomplished by applying translation (and when applicable rotation and scale) parameters to the succession of grid designators until the precision implied by the number of grid cell designator pairs is reached.

The city grid is nominally based on a locational reference system that can be tied to other reference systems. In the nominal system, the underlying locational reference system datum is the World Geodetic System 1984 (WGS-84). Geodetic coordinates with respect to this datum can be converted to coordinates in a large number of other reference systems, allowing the city grid designators to be used with respect to other systems and other geodetic datums allowing conversion to Universal Transverse Mercator (UTM) systems, State Plane Systems, National Grid Systems, other horizontal coordinate system, or map projection.

The city grid origin is defined at the ten minute of latitude and ten minute of longitude intersection nearest the city centroid. This places the origin within five minutes of latitude and longitude of the city centroid. The radial distance of the city grid origin is then always within about 10 km of the nominal city center.

Each grid is then defined based on this origin by placing a grid centered at the origin with a false easting and northing halfway between minimum and maximum numeric characters. Grid cells are identified by an easting cell designator paired with a northing cell designator with successive pairs of designators defining grid cells of increasing precision.

Highest level; least precision two numeric characteristics, East is always first, North is always second, minimum is always 0 and maximum is always 9.

The false easting puts the division between 4 and 5 at the grid origin north and east. Each highest level grid consists of a ten by ten region (100 grid rectangles).

Next lower level; higher precision, divides each numeric grid into a ten by ten grid (100 grid rectangles) area. East is always first, north is always second. Minimum is always 0 and maximum is always 9.

The false easting again puts the grid rectangle center at the division between 4 and 5.

Next lower levels repeat the numeric code above dividing each higher grid rectangle into a ten by ten rectangle area.

If each city grid origin is at an integer intersection of an even ten minutes of latitude and longitude, the first level numeric grid rectangles each cover an area of approximately 100 square kilometers with grid cells whose north-south extent is about 10 kilometers. Thus the entire set of first level grid cells covers a distance of about 100 kilometers from north to south and a shorter distance from west to east, depending on latitude. Alternatively, if it is preferred to establish the city grid system in miles, the first level numeric grid rectangles each cover an area of approximately 100 square nautical miles, or about 343 square kilometers with grid cells whose north-south extent is about 18.5 kilometers. Thus the entire set of first level grid cells covers a distance of about 185 kilometers from north to south and a shorter distance from west to east, depending on latitude.

Each second level city grid cell is {fraction (1/10)}^(th) of the next higher level grid cell, or 1 minute of latitude and longitude, about 1 km north to south, or, in a miles city grid system, 1850 meters north to south.

Each third level city grid cell is then {fraction (1/10)}^(th) of the second level grid, or 6 seconds of latitude and longitude, about 100 meters north to south, or, in a miles city grid system, 185 meters north to south.

Each fourth level city grid cell is then {fraction (1/10)}^(th) of the third level grid, about 10 meters north to south, or, in a miles city grid system, 18.5 meters north to south, around 340 square meters.

Since this fourth level grid corresponds to a resolution some five times more precise than un-aided GPS accuracy (with Selective Availability), a fifth level grid may not be required. Following the same {fraction (1/10)}^(th) rule as the higher level grids, a fifth grid cell would measure 1 meter on a side, or, in a miles city grid system, 1.85 meters on a side, well within the accuracy of differentially-aided GPS.

Cities close to each other can each employ their own city grid even when they overlap. When questions of which city grid occur the city code (or all the higher level codes) can be attached to remove ambiguity.

An example of a use of an ULA might be US.GA.ALB.13 to refer to an area, in a miles city grid system, about 20 kilometers wide southwest of the center of Albany Ga. Then .ALB.13.78 would refer to an area about 2 kilometers wide near the northeast corner of the previous example. So would .13.78 if the geographic context was established as Albany Ga.

The code .US.GA.ALB.13.78.27.14, in a miles city grid system, would refer to the smallest unit of about 9 meters within an explicitly defined place. .78.27.14 would refer to the same place in context.

B. EXAMPLE 1A

In addition to the example above which demonstrates one means for implementing the city grid, this example describes an alternative means for implementing the city grid based on the Transverse Mercator projection system.

In a preferred implementation a conventional map projection/coordinate system grid is selected. While Lambert Conformal Conic, Stereographic, or local tangent plane system might well be used, in this example, the Transverse Mercator (TM) projection is selected. The TM projection is preferred over other projections suitable for use in local mapping systems because it is most likely an available projection in many GIS and GPS platforms.

To make city centroid selection less contentious an issue, one preferably uses lists of centroids from the Digital Chart of The World (VMapO) or other sources and moves them to arbitrary points that are defined in controlled lists. In order to remove the slight differences in city centroids from different lists, and to standardize the method of fixing the preferred list, the city grids are centered at the nearest 0.05 degrees of latitude and longitude, assuring that the “centroid” is always within the 55 first level cell, and always within about 5.5 km of the center of the grid. This use of decimal degrees rather than values in minutes makes internal computations easier and less subject to complex issues such as repeating fractional values (i.e. 50 minutes=0.8333333333 . . . degrees).

In this example, the city grids are Transverse Mercator grids with the following characteristics:

Origin latitude and longitude “snapped” to the 0.05 degree increment south-west of the city centroid.

Scale at the origin=1.0

False easting 50,000 meters

False northing 50,000 meters.

Normal TM projection formulas as documented in Snyder (1987) and used in almost everyone's TM routines.

The grid cells for all level grids start at 00 in the south-west corner, increasing to 99 at the north-east corner following this simple pattern:

09 19 29 39 49 59 69 79 89 99 08 18 28 38 48 58 68 78 88 98 07 17 27 37 47 57 67 77 87 97 06 16 26 36 46 56 66 76 86 96 05 15 25 35 45 55 65 75 85 95 04 14 24 34 44 54 64 74 84 94 03 13 23 33 43 53 63 73 83 93 02 12 22 32 42 52 62 72 82 92 01 11 21 31 41 51 61 71 81 91 00 10 20 30 40 50 60 70 80 90

Each Level 1 grid cell covers a 10 km by 10 km square region on the ground

Each Level 2 grid cell covers a 1 km by 1 km square

Each Level 3 grid cell covers a 100 meter by 100 meter square

Each Level 4 grid cell covers a 10 meter by 10 meter square

The grid cells are exactly these distances north-south and east-west of the center of the grid.

The scale factor of 1.0 at the grid origin means that largest distance error is less than 4 meters over the extent of the grid.

As an example using the US.DC.WAS grid, the ellipsoidal distance from southwest corner to northeast corner is 141419.494 meters. Computed using the TM grid as though it was orthogonal one would compute a range using the Pythagorean theorem of 141421.356 meters, a difference of 1.862 meters.

These grids then can be used for very accurate distance estimates as well as making their use with any existing map quite simple. In addition, it should be noted that the grid cell designators can be easily computed from the output of any existing TM routine (such as those found in GPS receivers for user grids) using the TM parameters. For instance the position of the Smithsonian Institution in TM eastings and northings is:

52072.6 East and 48736.0 North.

The grid designators are simply extracted from the powers often one digit at a time, east followed by north as:

54.28.07.73 for ten meters, or 54.28.07.73.36 for a one meter level grid.

To put a grid designator value into a TM conversion, one makes easting and northing values from the grid designator in the same way.

For instance a random designator of:

39.12.46.15.53, results in: 31415 meters Easting and 92653 meters Northing or

39.12.46, results in: 31400 meters Easting and 92600 meters Northing.

C. EXAMPLE 2

In addition to the example above which demonstrates the logic and structure of the XYZ.12.34.56.78 format, this example describes the use of a grid format and ULA utilizing the XYZ.12.aa.34.aa format. The Country, State/Province, City and Proprietary Codes remain as described in the previous example, but the optional City Grid is structured differently. The grid code is still initially identified by a pair of numeric characters, and the city grid origin is defined at the ten minute of latitude and ten minute of longitude intersection nearest the city centroid as in the previous example. The definition of each grid and the false easting and northing, as well as the structure of the first grid level, is also as described in the preceding example.

The next lower level of the grid divides each numeric grid into a twenty by twenty grid (400 grid rectangles) area. East is always first, north is always second. The minimum is A from a character set consisting of ABCDEFGHJKLMNPQRSTUV, and the maximum is V. The false easting puts the grid rectangle center at the division between K and L.

The next lower level repeats the numeric code as described in the preceding example dividing each higher grid rectangle into a ten by ten rectangle area, and the next lower level repeats the alpha code described above in this example dividing each higher grid rectangle into a twenty by twenty rectangle area.

If the city grid is the same size as the preceding example, each second level city grid square (represented by the code XYZ.12.aa) is {fraction (1/20)}th of the first numeric grid square, 30 seconds of latitude and longitude, or about 920 meters north to south. The third level city grid square (represented by the code XYZ.12.aa.23) would result in a grid rectangle size of approximately 3 seconds of latitude and longitude, or about 92 meters north to south. The fourth level city grid square (represented by the code XYZ.12.aa.23.aa) would be {fraction (1/20)}th of the previous city grid square size, resulting in a grid rectangle size of approximately 0.15 seconds of latitude and longitude, or about 5 meters north to south.

It should be appreciated that it is possible to define embodiments in which these higher level portions are defined in terms of either numeric or alpha characters, or alternatively, in terms of mixed alpha and numeric characters.

D. EXAMPLE 3

This example demonstrates the different precision achievable by varying the size of the city grid of a particular district. This example uses a sample city grid designator “US.TX.AUS.45.45.77.45,” with a district centroid of 30 degrees, 17 minutes north latitude and 97 degrees, 45 minutes of west longitude for an Austin, Tex., city grid district with a district designator, “US. TX. AUS.” For a city grid easting and northing resolution of 1 minute of latitude and longitude for the largest resolution grid designator pair, the grid origin would be placed at 30 degrees, 17 minutes north latitude and 97 degrees, 45 minutes west longitude.

For numeric city grid designators with no rotation or scale, and with a false easting and northing of five grid cells, the designator “US.TX.AUS.45.45.77.45” would correspond to a geodetic position of 30 degrees, 15 minute, 45.0 seconds north latitude, and 97 degrees, 45 minutes, 15.0 seconds west longitude. The precision of the smallest grid cell would be one thousandth of a minute of latitude and longitude corresponding to approximately 1.6 meters of easting and 1.9 meters of northing. By reducing the number of designator pairs the precision of the implied geodetic position is also reduced. In this example, a designator of “.TX.AUS.45.45”, would refer to an area one tenth of one minute of latitude by one minute of longitude in area or approximately 185 meters north to south; “.AUS.45.45.77” would refer to an area one-hundredth of one minute by one-hundredth of one minute, or approximately 18.5 meters north to south.

IV. Exemplary Applications of WGRS

Set forth below are several exemplary applications of the WGRS. Examples 4 through 7 reflect situations in which the invention may be used and provide marked improvements in function and utility over traditional lat/lon based systems. Example 8 demonstrates certain aspects of the invention related to a particular geographic area and two maps of partially overlapping areas.

A. EXAMPLE 4

The subject invention may be used for general vehicular navigation, to drive from Los Angeles to the visitor's center at the Grand Canyon. The driver must first determine the address for the target location, and then input the address into the navigational system. There are several alternatives for locating the PLA or ULA. For example, the driver may read travel brochures that contain the ULA/PLA addresses; the driver may also review a map which contains ULA/PLA annotations; or the driver could just call the Visitor's Center and ask them for their PLA or ULA. Alternatively, the driver, using the input device, could search the PLA database to find if the Grand Canyon visitor's center has a PLA. Once the address is determined, the driver enters the PLA or ULA address into a navigational system, and the navigational system will direct the driver to the proper destination.

B. EXAMPLE 5

Second, the subject invention may be used to direct local traffic to a particular point of interest. For example, if the driver above is traveling along a highway and becomes hungry and desires to eat at a particular fast-food chain, the driver could interrogate the system data to find any nearby chain restaurants. The driver simply queries the navigational system for occurrences of the fast-food chain's PLA, and, since the navigational system is aware of its current location, the chain's restaurants may be listed by proximity. The driver simply selects one of the restaurants, and the navigational system directs the driver to that location. Additionally, a local restaurant may advertise an ULA or PLA for its location, so a driver, seeing a billboard or advertisement containing an ULA or PLA address, could input that address and be directed to the restaurant location. Because of the unique style of the addresses and features of the subject invention, these addresses are particularly easy to input with a minimum chance of error, decreasing the risk of accidents and increasing the likelihood of going to the desired location.

C. EXAMPLE 6

Third, the subject invention is particularly well suited for customization by individual or team users, facilitating intra-group communication and navigation. For example, if a group of hikers desires to split up and explore a particular area, they each could set their portable navigation devices to reference a custom grid with an appropriate grid size and location for the explorable area that allows sufficient resolution with a minimum number of digits or characters. Now, as the hikers communicate with each other or record interesting locational information, the data may be easily and accurately used and referenced to a meaningful location. This ability to set a user-defined reference point and grid size would also be useful for rescue teams performing search and rescue operations by allowing the search and rescue team to instantly establish a grid size and location for any search.

D. EXAMPLE 7

Fourth, the subject invention has emergency utility. For example, if a hiker above needs emergency assistance, the navigational system can provide a locational ULA that is easy to read and communicate by voice or numeric only key pad, which reduces both the ambiguity, risk and time involved in describing an emergency location. Alternatively, this ULA may be automatically communicated to emergency personnel if the navigational system integrates with a portable phone, two way pager, or other portable communication device.

E. EXAMPLE 8

An example illustrating the use of PLAs and ULAs in a specific geographical context, Yosemite National Park, will now be described. FIG. 6 illustrates a paper map with an assigned name of CA.YSB (indicated by identifying numeral 111). Within the boundaries represented on this map, the following PLAs have been reserved:

Description of Corresponding FIG. 6 PLA Location identifying numeral HFDM Half Dome 115 1 Ahwahnee Hotel 112 GCRP Glacier Point 114 YSMF Lower Yosemite Fall 113

FIG. 7 illustrates a district with an assigned name of CA.YSM (indicated by identifying numeral 120). Within this district, the following PLAs have been reserved:

Description of Corresponding FIG. 7 PLA Location identifying numeral HCHY Hetch Hetchy 121 11 White Wolf 122 NENT Big Oak Flat Entrance 123 GCRP Glacier Point 126 WENT Arch Rock Entrance 124 BDGP Badger Pass 125 1 Wawona Information Center 128 SENT South Entrance 127

The following points should be noted from this example:

First, the name CA.YSB is for the specific map included in FIG. 6, and not for a district in which all of the area contained on the map is included. This feature allows assignment of specific PLAs for specific maps without regard to the district, thereby providing clarity in situations where the area covered by the map overlaps one or more districts.

Second, the name CA.YSM is the name of the district in which the area included in the map in FIG. 7 is located, thereby allowing areas included within this map to be referenced by either PLAs (e.g. CA.YSM.HCHY) or ULAs (e.g. CA.YSM.32.84.23.43) without the need to re-identify the name of the district or map.

Third, the areas covered by the CA.YSM district and the CA.YSB map overlap, allowing PLA references to either the YSM district or the YSB map. (Note also that the system might also define YSB as a district which could be utilized in determining ULAs with reference to the YSB district, in which case the YSB and YSM districts would also partially overlap.)

Fourth, the PLAs for particular locations may either be identical except for the district name (e.g. GCRP in FIG. 6 and GCRP in FIG. 7 refer to the same location) or identical PLAs may apply to different locations in different districts or on different maps (e.g. “1” in FIG. 6 and “1” in FIG. 7 refer to different locations on each of the respective maps). This is consistent with the principle that a PLA need only be unique within the district in which it is defined.

All of the features described in this example are designed to allow an initial manual or electronic input (either a district code, cell code, or specific map code) which allows users to use PLAs or ULAs identified on a specific map with a minimum number of keystrokes, thereby minimizing data entry, confusion, and ambiguity.

V. Examples of Software Implementation

Examples 9, 10, and 11 demonstrate certain characteristics of files, pseudo-codes, and program screens of particular embodiments of the invention. (Note that the data contained in the files is provided for illustrative purposes only).

A. EXAMPLE 9

In this example, formats of specific files that are used in one implementation of the subject invention are described. Four files are described: GO2CITY.DAT, STATES.DAT, PROPGO2.DAT, and COUNTRYS.DAT.

The GO2CITY2.DAT file, illustrated in FIGS. 8a-8 b, defines the reference points for a plurality of pre-defined districts centered around specific cities. For each reference point, there is provided the name of the district, the name of the reference point, and the global coordinates of the reference point. Thus, the first entry of this file “AK, ANC, Anchorage, 149W54, 61N13,” indicates that there is a district in the state of Alaska centered around Anchorage, with the reference point thereof having the following global coordinates: 149W54,61N13.

The STATES.DAT file, illustrated in FIG. 9, simply defines the mnemonics used in GO2CITY2. DAT to define states.

The PROPGO2.DAT file, illustrated in FIGS. 10a-10 c, defines the proprietary names which have been reserved for each district. This file correlates each such proprietary name with the global coordinates associated with that name. Thus, the first entry of this file, “US.CA.NWB.MAC2, 117W52.360, 33N39.549” indicates that, in a district centered around Newport Beach, Calif., there is a MacDonalds having the following global lat/lon coordinates address: 117W52.360, 33N39.549.

The COUNTRYS.DAT file, illustrated in FIG. 11, simply defines the country mnemonics used in PROPGO2.DAT.

B. EXAMPLE 10

This example illustrates screen formats as displayed on an output device in an implementation of the subject invention. FIG. 12a is a screen illustrating the input of an ULA or grid address into a navigational system, with the system determining and outputting corresponding latitude and longitude coordinates. FIG. 12b illustrates the input of a PLA, with the system determining and outputting corresponding latitude and longitude coordinates. FIG. 12c illustrates the capability of the system to interpret the context, i.e. district address, of previous addresses, and to assume that the same distinct addresses applies to subsequent specific addresses until notified otherwise. In this specific example, the proprietary name MAC2 was input, with the system assuming that the district name associated with the previous example relating to MAC1, i.e., the CA.NWB. district name, applied to this example as well. Thus, in FIG. 12c, only the identifier “MAC2” need be input to the system, it being assumed that the district identifier “CA.NWB” applies to this request as well.

C. EXAMPLE 11

This document is a functional description of a computer program, Go2Grid, which embodies one or more aspects of the subject invention. The program is written in the “C++” programming language and its purpose is to demonstrate the feasibility of conversion between city grid and proprietary codes and geodetic coordinates.

Program flow is described using a series of pseudo-code statements. The functions required to perform these tasks are described. The data variable types and structures are defined. The parameters required for implementation of two possible city grid designators are defined.

Program Flow Set all defined parameters to their default values Northern latitudes are positive Eastern longitudes are negative The assumed geodetic datum is World Geodetic System 1984 (WGS-84) The last geodetic position is used to initialize the City Grid designator. The user screen is initialized Monitor keystrokes or navigation receiver input For any City Grid designator change Parse user input If change in City Code Compute city position from designator Fill City Code Fill Country and State Codes If change in State Code Fill Country and State Codes If change in Country Code Fill Country Code If change in entire City Grid Designator If a Universal Go2 Code Fill Country, State, City and Grid Codes If a Proprietary Go2 Code Fill Proprietary Code Compute geodetic coordinates for this Go2 Designator For any change in geodetic coordinates Parse user input If user has requested a Universal Code If current geographic context is changed Get Go2 Codes from latitude and longitude Find closest city Set new City Grid center Fill Country, State, City codes Compute City Grid Codes for each level of precision Reset User Screen display Continue

Functions

The following functions are used by the Go2Grid sample program, an embodiment of the city grid concept:

getdeg( ) extracts decimal degrees from character strings grange( ) computes geodetic range between two positions dmsdeg( ) extracts degrees, minutes, seconds from decimal degrees degdms( ) forms decimal degrees from degrees, minutes, seconds getcenter( ) computes geodetic coordinates of City Grid center from city centroid getgrid( ) computes City Grid codes for level of precision getkeys( ) parses user keyboard input parsego2( ) parses Go2 City Grid designator addlatlon( ) concatenates next level of precision onto geodetic coordinates getnextcity( ) finds next city in current state/province list getprevcity( ) find previous city in current state/province list getcost( ) fills Go2 City Grid designator with country and state/province codes putscreen( ) fills display with current city Grid designator and geodetic coordinates getnextstate( ) finds next state/province in current country list getprevstate( ) find previous state/province in current country list

Types and Structures

The Go2Grid embodiment sample program defines the following variable structures in addition to the usual character, integer, float, and double types:

typedef struct ccstruct {

char city_code[4];

char city[60];

char state_code[3];

char state[60];

char country_code[3];

char country[60];

char longitude[32];

char latitude[32];

double lat;

double lon;

double centerlat;

double centerlon;

};

typedef struct latlonstruct {

int latdeg;

int latmin;

int latsec;

int londeg;

int lonmin;

int lonsec;

};

Program Definitions

The following definitions are used within the Go2Grid sample program:

/* grid types */ /* a gridtype == 1 is numeric with 10 minutes, 1.0, 0.1, and 0.001 grids */ /* a gridtype == 2 is alphanumeric with 10, 0.5, 0.05 and 0.0025 grids */ #define GRIDTYPE 1 #define TITLE “Go2 and Geographic Coordinate Converter” #define VERSION “(4/3/96)” /* lines */ #define TITLELINE 1 #define GO2CONTEXTLINE 5 #define GEOCONTEXTLINE 10 #define HELPLINE 15 #define MESSAGELINE 18 #define COUNTRYLINE 20 #define STATELINE 21 #define CITYLINE 22 #define GO2LINE 23 #define LATLINE 24 #define LONLINE 25 #define INCOL 23 #define OUTCOL 5 #if GRID TYPE==1 /* GRID GRAIN */ #define GRIDKIND “Numeric City Grid” #define GRIDDEF “Grid Precision: Level 1=1.0′; Level 2=1.0′; Level 3=0.1′; Level 4=0.01′“ #define GRIDCHARS “Designators Levels 1, 2, 3 and 4: [01232456789]” #define LEVEL 1_EGRAIN 10.0 #define LEVEL 1_NGRAIN 10.0 #define LEVEL 1_ECHARS “0123456789” #define LEVEL 1_NCHARS “0123456789” #define LEVEL 1_EGRIDS 10 #define LEVEL 1_NGRIDS 10 #define LEVEL 2_EGRAIN 1.0 #define LEVEL 2_NGRAIN 1.0 #define LEVEL 2_ECHARS “0123456789” #define LEVEL 2_NCHARS “0123456789” #define LEVEL 2_EGRIDS 10 #define LEVEL 2_NGRIDS 10 #define LEVEL 3_EGRAIN 1.0 #define LEVEL 3_NGRAIN 0.10 #define LEVEL 3_ECHARS “0123456789” #define LEVEL 3_NCHARS “0123456789” #define LEVEL 3_EGRIDS 10 #define LEVEL 3_NGRIDS 10 #define LEVEL 4_EGRAIN 0.010 #define LEVEL 4_NGRAIN 0.010 #define LEVEL 4_ECHARS “0123456789” #define LEVEL 4_NCHARS “0123456789” #define LEVEL 4_EGRIDS 10 #define LEVEL 4_NGRIDS 10 #else if GRIDTYPE==2 #define GRIDKIND “Alphanumeric City Grid” #define GRIDDEF “Grid Precision: Level 1=10′; Level 2=0.5′; Level 3=0.05′; Level 4=0.0025′” #define GRIDCHARS “Designators Levels 1&3:[01232456789]; Levels 2&4:[ABCDEFGHJKLMNPRSTUVW]” /* GRID GRAIN */ #define LEVEL 1_EGRAIN 10.0 #define LEVEL 1_NGRAIN 10.0 #define LEVEL 1_ECHARS “0123456789” #define LEVEL 1_NCHARS “0123456789” #define LEVEL 1_EGRIDS 10 #define LEVEL 1_NGRIDS 10 #define LEVEL 2_EGRAIN 0.5 #define LEVEL 2_NGRAIN 0.5 #define LEVEL 2_ECHARS “ABCDEFGHJKLMNPRSTUVW” #define LEVEL 2_NCHARS “ABCDEFGHJKLMNPRSTUVW” #define LEVEL 2_EGRIDS 20 #define LEVEL 2_NGRIDS 20 #define LEVEL 3_EGRAIN 0.05 #define LEVEL 3_NGRAIN 0.05 #define LEVEL 3_ECHARS “0123456789” #define LEVEL 3_NCHARS “0123456789” #define LEVEL 3_EGRIDS 10 #define LEVEL 3_NGRIDS 10 #define LEVEL 4_EGRAIN 0.0025 #define LEVEL 4_NGRAIN 0.0025 #define LEVEL 4_ECHARS “ABCDEFGHJKLMNPRSTUVW” #define LEVEL 4_NCHARS “ABCDEFGHJKLMNPRSTUVW” #define LEVEL 4_EGRIDS 20 #define LEVEL 4_NGRIDS 20 #endif

VI. Internet-Based Automatic Location Referencing System

FIGS. 13-22 are used to describe a preferred embodiment of an automatic location referencing system using the WGRS described above. It should be noted that although this aspect of the present invention could be implemented with other types of geographical referencing systems, it is preferably implemented with the WGRS to take advantage of the features described herein.

FIG. 13 depicts an operational environment of the automatic location aspect of the present invention according to a preferred embodiment. A portable-computing device 1302 is installed in a mobile unit such as an automobile 104. Alternatively, the portable-computing device 1302 may be carried on the person of individual users. In yet another embodiment, the present invention can be implemented using a non-portable computing device such as a general-purpose desktop computer or the like.

However, for the purposes of this example, the device 1302 is referred to as the portable-computing device. In one embodiment, the portable-computing device 1302 receives data from Global Positioning System (GPS) satellites 1310 for location identifying purposes. This is one example of a means for automatic location identification, as shown by block 1301 labeled “ALI Example 1.” A second example of a means for automatic location identification is shown as block 1303 labeled “ALI Example II.” ALI Example II 1303 is intended to represent a means for automatically identifying the location of a device, such as device 1302, via a cellular transmission. Example II 1303 typically uses triangulation techniques in conjunction with at least two cellular base stations, or distance measuring techniques from three cellular base stations, such as the base station 1306.

Additional means for ALI can also be used in alternate embodiments of the present invention. For example, the automatic identification signals commonly used in land-line telephonic devices (“ANI” and the like), can be used in conjunction with a database lookup table to identify a callers fixed location.

In any case, any well-known means for automatically identifying a caller's geographical location can be used in various embodiments of the present invention. In fact, future methods, not yet known, but used for identifying the location of a mobile unit, such as the mobile unit 1302, are within the scope of the present invention. Accordingly, the use of the examples of a cellular network and a GPS system should not be construed to limit the scope and breadth of the present invention.

The portable-computing device 1302 has the capability for wireless communications. In this example, one use of the wireless communication feature is to connect the portable-computing device 1302 via a wireless network gateway to a computer network such as the Internet 1318. The wireless communication feature of the present invention is also used for providing standard telephony functions. In addition, as stated above, the wireless communication feature of the present invention can also be used to implement ALI functionality in accordance with the principals described herein.

In one example, cellular technology is used to implement the wireless communication feature of the present invention. In FIG. 13, the base station 1306 and the mobile switching office 1308 represents a portion of a typical cellular network. The base station 1306 sends and receives radio signals to and from the portable-computing device 1302. The mobile switching office 1308 is coupled to the base station 1306 via standard telecommunication transmission lines. Likewise, the mobile switching office 1308 is coupled to the public switched telephone network 1312 via standard telecommunication transmission lines. The public switched network 1312 is coupled to the Internet 1318 via a point-of-presence, which is typically implemented using high bandwidth T3 telecommunication channels or the like.

A primary server 1314 is coupled to the Internet 1318. The primary server 1314 is used to interface with the portable-computing device 1302 as described below. The primary server 1314 is coupled with a database or persistent storage device 1316. A plurality of enhanced servers 1315 are connected to the Internet 1318. The enhanced servers 1315 provide location specific data to the portable-computing device 1302. The primary server 1314 selects a particular enhanced server 1315 to be connected to the portable-computing device 1302 in accordance with a database query as described below.

Note that the present invention is described in terms of a primary server 1314 and one or more enhanced servers 1315. However, this does not mean that separate physical servers must be used to implement these functions. Indeed, a single server or multiple servers can be used to implement the functions of the primary server 1314 and the enhanced servers 1315 as described herein. Thus, the use of these terms should not be construed to limit the scope and breadth of the present invention to the physical configurations described in these exemplary embodiments.

The cellular network is just one example of a technology that can be used to implement the wireless communication feature of the present invention. In other embodiments, different types of wireless technology can be used, such as low orbit or geosynchronous orbit satellite communications. In fact, any type of wireless technology can be used to provide the wireless communication feature of the present invention.

Further, the Internet 1318 is used in a preferred embodiment of the present invention due to its wide use and availability. However, any type of computer network can be used in alternate embodiments of the present invention. As such, the use of the examples of a cellular network and the Internet 1318 should not be construed to limit the scope and breadth of the present invention.

Details of the portable-computing device 1302 are depicted in FIG. 14. Typically, the portable-computing device 1302 comprises a client computer 1404, a persistent storage device or database 1408, a display screen 1412, a keypad input device 1414, a speech interface 1418, an ALI device 1406, a wireless transceiver 1402 and a telephony device 1410.

Note that these components, such as the ALI device 1406 and/or the wireless transceiver 1402 may be imbedded within the portable-computing device 1302. Alternatively, such components may be implemented as discrete external devices coupled to the portable-computing device 1302 through external ports, such as RS-232, SCSI, USB ports or the like.

In addition, many of the components described above are optional and depend on each specific implementation of the present invention. For example, the speech interface 1418 and the ALI device 1406 are optional components. Embodiments of the present invention that operate without an ALI 1406 accept manual input of location information via the keypad 1414 or other input device.

Any type of general or special purpose computer system can be used to implement the portable-computing device 1302. Examples of such devices include standard laptop computers, automobile computers and personal digital assistant devices (PDAs). Typically the portable-computing device 1302 includes a CPU, local working memory, or RAM, non-volatile program memory, or ROM, and some form of non-volatile external memory for data storage 1408 such as any type of NVRAM, or magnetic or optical disk storage systems. An example of a general-purpose computer system that can be used to implement the present invention is described below with reference to FIG. 22.

The display screen 1412 is used to display output from the portable-computing device 1302. The keypad device 1414 is coupled to the portable-computing device 1302 and is used for inputting data. For example, location data can be manually input from the keypad device 1414.

In this example, a speech interface 1418 is also coupled to the portable-computing device 1302. The speech interface 1418 uses voice recognition techniques to accept spoken commands from users for controlling the portable-computing device 1302. The speech interface 1418 is used in a preferred embodiment to allow users to control the computer 1404 via spoken voice commands for promoting safe driving conditions while operating the portable-computing device 1302 from an automobile or the like.

The persistent storage device 1408 is used to store application programs such as a web browser and one or more specialized application programs used to implement the present invention as described in detail below. Such application program(s) is/are referred to herein as the “Go2 Application program,” which is described in detail below. In addition, location and other information are stored as data packets on the local persistent storage device 1408, as described in detail below. Depending on the storage capacity of the persistent storage device 1408, one or more database lookup tables can be stored therein and used for translating, for example, between a lat/lon coordinate system and the WGRS. However, all systems that are enabled in accordance with the present invention will generally have the capability to translate between a lat/lon coordinate system and the WGRS using the universal addressing scheme as described above. Additional storage requirements are needed to translate to and from the WGRS using proprietary addresses.

The wireless transceiver 1402 is used to send and receive data between the portable-computing device 1302 and other devices such as the servers 1314 and 1315 coupled to the Internet 1318.

The ALI device 1406 is used to track the position, and possibly the speed and bearing of the portable-computing device 1302. As stated above, any device can be used that performs ALI functionality. Examples of well-known ALI devices are GPS systems, low orbit satellite systems, geosynchronous orbit satellite systems, telephone number identification systems, cellular network triangulation methods, etc. In this example, telephone number identification systems (ANI) can be used in conjunction with a database lookup table to determine predefined fixed positions of users based on an assigned telephone number.

FIG. 15 is a block diagram depicting functional components of an application program or program(s) running on the portable-computing device 1302 in accordance with an embodiment of the present invention. As stated, the application program(s) is/are referred to herein as the “Go2 application program” 1500.

The Go2 Application program 1500 is provided with a web browser component 1502. The web browser component 1502 is used to perform web browser functions for the portable-computing device 1302. In fact, in one embodiment, a standard web browser is used to implement the web browser component 1502 of the present invention. Alternatively, customized web browser code can be imbedded into the Go2 Application program 1500. In either case, the web browser module 1502 provides standard web browser functions. Such functions would be apparent to persons skilled in the relevant art(s). As shown, the web browser component 1502 is coupled to a web server 1510.

Accordingly, the web browser module 1502 interprets data streams sent from the server 1510 and displays text and/or graphics therefrom. The text and/or graphics are displayed on the display screen 1412. The web browser component 1502 also accepts input from users via the keypad 1414 or other input devices. Preferably, the data streams transmitted by the server 1510 are in a standard format, such as HTML, a modified version of HTML or the like. In this fashion, generic web-browsing tools can be used to interface with the web server 1510 and the U/I module 1506 (see below) of the present invention.

The User Interface (U/I) module 1506 is coupled with the web browser module 1502. The U/I module 1506 is used to prompt the user for information including user preferences and category selections to be used for subsequent information requests, (i.e. on-line database queries) as described below. The U/I module 1506 preferably performs at least some functions locally. That is, at least some functions provided by the U/I module 1506 are performed without a live connection to the server 1510. These functions are referred to herein as “local functions” and are described in detail below. For example, one local function provides a menu that is displayed which allows users to select from a list of predefined categories. In this example, users select a category of interest for formulating a database query that is to be used in a subsequent on-line session with the primary server 1314. Details of this aspect of the present invention are described below.

A data packet builder and parser module 1504 (hereinafter “data packet module”) is coupled to the U/I module 1506. The data packet module 1504 is used to construct data packets, which are stored on the local storage device 1408. These data packets are subsequently read by the server 1510 and used to formulate on-line database queries. The data packet module also parses data packets received from the server 1510. Details and examples of data packet contents are described below.

An ALI polling module 1508 is used to poll the ALI device module 1510. The ALI device 1406 provides location, bearing and speed information to the Go2 Application program 1500. This information is then used to build data packets that are stored in the local data storage device 1408. Details of a process that can be used to implement the ALI polling module 1508 is described below.

FIG. 16 is a flowchart that generally describes an overall process in accordance with an embodiment of the present invention. The process begins with step 1602. In step 1602 the process determines the current location. The current location can be automatically determined from an ALI device 1406, or can be manually input from the user. After the current location is determined, control passes to step 1604.

Next, in step 1604, the process determines the desired location and specific database query. The U/I module 1506 may be used to present the user with one or more selectable menu choices. Alternatively, in one embodiment, the U/I module recognizes numerous requests based on commonly used terms such as “burgers,” “shopping,” “banks,” or the like. In this fashion, the user can formulate a complex database query by simply picking and choosing among the menu items presented or the user may perform a simple database query by merely inputting one or more common terms.

For example, the user may wish to formulate a database query for finding all fast-food restaurants within a five-mile radius. The desired location may be different from the current location, if for example, the user specifies some time in the future. For example, the user may wish to find fast-food restaurants within five-mile radius from a location one hour in the future. In this example, the process can use the current location, current speed and bearing to predict the desired location. In another example, a routing program can be used to determine the desired location based on a pre-defined route input by the user.

Next, in step 1606, the desired location is converted to the WGRS, if necessary. For example, GPS devices typically use the geodetic latitude and longitude system for describing location data. In this case it may be necessary to convert to the WGRS in order to take advantage of the unique features of the referencing system as described herein.

In another example, a user may manually input location information. Again, such manual input is preferably entered in the WGRS format because of its ease of use lower susceptibility to errors. If Go2 data is entered directly, either manually or by the ALI device 1406, then step 1606 is bypassed.

Next, in step 1608 the current location information and the database query information is stored in the local storage device 1408. Typically, this information is stored in a pre-defined data format referred to herein as a “data packet.” The format of a typical data packet is described below. Next, in step 1610, the portable-computing device 1302 connects to the primary server 1314.

In step 1611, the primary server 1314 reads the data packet stored in step 1608. From this information, a database query is formed as indicated by step 1618. Next, in step 1620, the process retrieves the results from the database query and sends them to the client, as indicated by step 1620. The process ends with step 1622.

FIG. 17 is a flowchart depicting a process that can be used to implement a portion of the Go2 Application software 1502. The process begins with step 1702. In step 1702, the U/I module 1506 offers the user one or more options for specifying how location information is to be determined. Typically, if an ALI device is attached, it is used to automatically provide location information to the Go2 Application software 1500. Alternatively, one or more additional methods for specifying location information are typically offered. In this example, as indicated by the block 1701, the user has the option to specify that the process retrieve location information from the attached GPS receiver. In one example, the user can select between the current GPS location and a projected location based on a specified elapsed time.

In addition, predefined locations, such as home or office can be specified. Typically, the location coordinates are preprogrammed as a user preference. In a preferred embodiment, the WGRS is used to specify such pre-programmed user preferences. Alternatively, in this example, the user can access a map in which to specify a location. The map database can either be provided locally by the client 1404, or can be provided remotely through a connection with a server 1510.

In another example, a routing program (either on-line or locally) can be used to project future locations and to specify one or more waypoints along a pre-defined route. In addition the user has the option to manually specify location information. Advantageously, manual input is in the form of the Go2 coordinate system.

It should be noted that block 1701 lists a few examples of the types of parameters that can be specified by users for determining location information in accordance with a preferred embodiment of the present invention. Alternate embodiments may comprise selections that are very different from the examples provided herein. The actual contents of menu items displayed by the U/I module 1506 depend on each specific implementation of the present invention. As such, the examples used herein should not be construed to limit the scope and breadth of the present invention.

In any case, once location information is specified in step 1702, control passes to step 1703. In step 1703 the U/I module 1506 prompts the user for criteria used to formulate a subsequent on-line database query. In this example, the user selects a category of interest, one or more category features, a search radius and other selection criteria. One method that can be used to implement this step is to display a selectable menu to the user as shown in block 1704. The U/I module 1506 is used to perform this function.

For example, the menu 1704 comprises category selections such as: restaurants; banks; ATM machines; hotels; copy centers; libraries; museums; gas stations; weather reports; car dealers; auto repair shops; maps; directory assistance; police stations; hospitals and the like. In this fashion, for example, the user can find nearby restaurants by first selecting the corresponding category of interest, as shown in block 1704.

In addition, the menu shown in block 1704 allows users to specify one or more features associated with the selected category. Feature selections narrow or drill-down the subsequent database search. For example, the user may only be interested in restaurants that accept a particular type of credit card, have a particular dress code, or provide goods within a particular price range. Accordingly, the user narrows the subsequent database search by simply selecting one or more appropriate features associated with the selected category. Multiple levels of category features can be presented based on the needs and requirements of each specific implementation of the present invention.

Another parameter that is preferably specified by the user is a search radius. For example, the user can specify that the search only include points of interest within a particular radius from the current or desired location.

It should be noted that these are just some examples of the types of parameters that can be specified by users in accordance with a preferred embodiment of the present invention. Alternate embodiments may comprise menu items that are very different from the examples provided herein. The actual contents of menu items displayed by the U/I module 1506 depend on each specific implementation of the present invention. As such, the examples used herein should not be construed to limit the scope and breadth of the present invention.

Preferably, users can also define one or more user preferences. These user preferences are used as default parameters if they are not over-ridden by current selections. In this fashion, user input is minimized.

Once the database query parameters are specified, control passes to step 1705. In step 1705, the process determines whether the location information is the WGRS format. If it is not, it is converted to the WGRS in step 1706. In one embodiment, this conversion takes place locally. In another embodiment, the primary server 1314 performs the conversion upon connection with the client 1404. Next, in step 1707 a data packet 1708 is created. This data packet 1708 is then stored on the local storage device 1406.

In one example, the data packet comprises the following information as depicted by block 1708. The current location, including the speed and bearing, if available. As stated, depending on the specific implementation of the present invention, this may or may not be in the WGRS format. If it is not, the primary server can convert it into the Go2 coordinate grid system.

As indicated by item 4, an estimate for an intended route, based on an elapsed time may be included in the data packet. For example, a user may wish to stop for the night in one hour from the present time. In this example, an estimate of a future location may be included in the data packet. The client 1404 or the server 1314, depending on each specific implementation of the present invention, can perform the future location prediction. If the server 1314 performs the location prediction, a time period is specified in the data packet 1708.

In addition, routing information may also be specified as indicated by item 5. A routing program or the like can provide this information. If routing information is not given, a projected location is determined based on the present position, speed and bearing. Of course, if routing information is not provided, the server 1314 assumes the user will remain on the current road for the specified elapsed time. Further, the server can use additional information, such as traffic and/or weather conditions to provide more accurate predictions. This additional information can originate from anywhere on the Internet 1318 or from an Intelligent Transportation System.

As indicated by item 6, predefined user preferences are also included in the data packet 1708. This can include, for example, information such as whether the user is on a business trip or on vacation. User preferences are used to further narrow the database query. For example, if the user is looking for hotel accommodations, the program can find appropriate selections based on whether the user is on business or vacation. Preferably, the user preferences are entered one time and are not changed for every database query to minimize input requirements.

Item 7 represents preferences that override predefined user preferences for the duration of the next database query. Thus, for example, a pre-defined user preference may be to find places or interest that are within 5 miles. This user preference generally applies to every database query. However, because the user is currently driving in a rural area, the user may prefer to focus a search in a wider radius, say 20 miles. The next time the user launches a database query, if the radius is not specified, it reverts back to the 5-mile user preference value. Item 8 represents other database query parameters that may be present.

It should be noted that the above items that comprise the data packet 1708 are just a few examples of the type of data that may comprise a data packet in accordance with a preferred embodiment of the present invention. Alternate embodiments may comprise very different data items than the above examples. As such, the examples used herein should not be construed to limit the scope and breadth of the present invention.

FIG. 18 is a flowchart depicting a process that can be used to implement a process performed by the primary server 1314 upon connection with the client 1404. Step 1802 represents a step where the client 1404 connects with the server 1314. Next, in step 1804, the server 1314 determines if a data packet 1708 is available on the client data storage device 1408. If a data packet is available, the location information is extracted therefrom, as indicated by step 1810. Control next passes to step 1814, which is described below.

If it is determined in step 1804, that a data packet is not available, control passes to step 1806. In step 1806 the user is offered an opportunity to download the Go2 Application software 1500. Next, as indicated by step 1808, control passes to step 1824 if the user accepts the offer to download the Go2 software 1500. In step 1824, the Go2 Application software is downloaded to the client 1404.

Next, in step 1826, the Go2 Application software 1500 is executed on the client 1404. During the execution of the Go2 Application software 1500, the user inputs user preferences, location specifications and other database query parameters, as described above. After such information is entered, the Go2 Application software 1500 creates a data packet 1708 and stores it on the data storage device 1408. After this occurs, control passes back to step 1802 as described above. Now the user is enabled so that he or she can take advantage of the automated features of the present invention.

As indicated by step 1808, if it is determined that the offer to download is rejected, control passes to step 1811. In step 1811, the user is provided with one or more web pages that accept location information, user preferences and the like in a manner similar to that described above with reference to the Go2 Application U/I module 1506. In this fashion, the primary server 1314 can provide services to users that are not enabled with the Go2 Application software 1500. Next, in step 1812, the primary server 1314 reads the location information entered in step 1811. Control next passes to step 1814.

In step 1814, the location information, (either manually entered in step 1811, or automatically extracted from the data packet in step 1810), is converted to the WGRS, if necessary.

Next, in step 1814, the server 1314 performs a database query. The object of the database query is to find an appropriate server 1315 that provides the type of service requested by the user. This aspect of the present invention is described in detail below, with reference to FIG. 19. The process ends as indicated by step 1822.

FIG. 19 is a flowchart and block diagram useful for describing the interaction and processing between the client 1404, the primary server 1314 and an enhanced server 1315. The process begins with step 1902. In step 1902, the user selects a category of interest and other data from the menu 1701 as described above.

Next, In step 1904, the data packet module 1504 builds the data packet 1708. The data packet 1708 is then stored on the local storage device 1408. Next, as indicated by step 1906, the data packet 1708 is transmitted to the server 1314. At this point the primary server 1314 parses the data packet 1708 and formulates a database query on the database 1316.

In accordance with one embodiment of the present invention, the persistent storage device 1316 contains a list of the enhanced servers 1315 that provide location specific information in accordance with the present invention. In particular, the primary server 1314 searches its database 1316 and retrieves a specific Uniform Resource Locator (“URL”) that satisfies the database search criteria entered by the user, as described above.

It should be noted that the enhanced 1315 servers are preprogrammed to provide data that is customized in accordance with a specified location. Thus, the enhanced servers are preprogrammed to accept and respond to a location identifier, preferably in the WGRS.

Next, in step 1912, the client 1404 receives a second data packet 1914. The second data packet 1914 comprises the URL result from the database query, plus any other additional information that may be required by the enhanced server 1315, as specified in the database 1316.

Next in step 1916, the Go2 Application launches the web browser component 1502 and automatically connects to the URL received in the data packet. Specifically, the browser is programmed to accept the URL as the default page so that it is automatically loaded upon connection to the Internet 1318.

It is noted that the present invention is described in terms of a primary server 1314 and a plurality of enhanced servers 1315. In this first embodiment, the primary server performs a database search that results in an address for an enhanced server that can satisfy the customer's database query. However, the present invention is not restricted to this configuration. An alternative embodiment comprises a plurality of enhanced servers but no primary server.

For example, in one embodiment, the Go2 Application software 1500 provides the services provided by the primary server 1314 in the above example. In another embodiment, the user determines which one of the enhanced servers to connect to. In this example embodiment, each of the enhanced servers 1315 is preprogrammed to parse the data packet 1708 and extract location information therefrom, as described above.

FIG. 20 is a flow chart that is useful for describing a method that can be used in the Go2 Application program to implement a feature of the present invention for automatic location data collection. The flowchart in FIG. 20 represents an endless loop and therefore has no defined beginning or end point.

As indicated by step 2002, the process determines whether an ALI device 1406 is attached. If an ALI device 1406 is attached, control passes to step 2006. In step 2006 the ALI device 1406 is polled to retrieve location data therefrom. Next, in step 2010, the process determines whether the retrieved location data indicates a change from the previous poll. If step 2010 indicates that the location has not changed (i.e. the user is not moving), control passes to step 2004, where the process sleeps for a predetermined time period until it repeats itself in step 2002.

If step 2010 indicates that the location has changed, control passes to step 2012. In step 2012 the process determines if the client 1404 is on-line. If so, control passes to step 2014. If the client is not on-line, control passes back to step 2004.

In step 2014, the process determines if a server 1314 is currently requesting that location data be updated. The server in this example, can be any server, such as the primary server 1314 or any enhanced servers 1315. If the server is requesting updated location information, the current position, preferably in the WGRS format, is transmitted to the server in step 2016. If the server is not requesting an update, control passes back to step 2004.

As indicated by the blocks 2020 and 2024, the server uses the Go2 location information for performing a database query. The results are then sent back to the client and as indicated by block 2026.

An advantage of the present invention is that users can benefit from the virtually unlimited storage capacity and real-time updates of the Internet 1318. Because the Internet 1318 is used in a distributed fashion to provide users with customized location related information, the information provided to users can be as detailed as desired. For example, in addition to using maps to determine driving directions, more detailed information, such as site plans, building floor plans, photographs of the destination, private road configurations and the like can be presented to users.

In addition, because the direction in which the user is traveling can be determined, that information can be used to select a proper orientation for the extended information, such as a site plan, for example. FIG. 21 depicts an example of a site plan that shows building configurations, parking lots, etc. In this example, the site plan in FIG. 21 is stored as digitized photograph. The orientation of the digitized photograph displayed to the user depends on the user's direction of travel so that the proper orientation is displayed.

VII. Method of Creating a Nesting Grid Structure for a Geographic Referencing System and Method of Addressing Using the Same

An exemplary method of creating a hierarchical grid system of the WGRS will now be described followed by a description of a nesting grid system and method of creating and using the same.

A grid system is first created by taking one or more geographical areas such as the geographical area(s) represented by United States and any other countries and subdividing the geographical area(s) into numerous districts or regions. The regions are preferably strategically located, sized, and named with reference to cities or other geographic or political features in order to make it easy to associate the regions with such commonly known features. Although regions may be centered around or centered on geographic or political features, the method of creating a nesting grid structure will only be described below with respect to regions centered around or centered on more major cities or population areas. It should be noted, the nesting grid structure may also be used in conjunction with regions centered around or centered on geographic or political features.

With reference to FIG. 22, after the regions have been selected and named, a reference point or regional grid origin 4010 is chosen for each region, and a regional grid 4020 is placed relative to the regional grid origin 4010. The regional grid origin 4010 has a known address within a global referencing system such as the World Geodetic System (WGS). The regional grid origin 4010 is preferably positioned at the ten minute of latitude and ten minute of longitude intersection nearest the city center or city centroid for a major city or population area 4025 about which the region is located. This places the regional grid origin 4010 within above five minutes of latitude and longitude of the city centroid. It is a common occurrence for various gazetteers and databases to contain different geographic coordinates for the centers of political subdivision, and by positioning the regional grid origin at the next closest ten minute of latitude or longitude it is probable that the same regional grid origin will be obtained irrespective of which gazetteer or database is used.

Each regional grid 4020 is preferably a 10 cell×10 cell grid (100 grid rectangles or cells), where each grid cell 4030 is 10 km×10 km. Thus, the regional grid 4020 is preferably 100 km×100 km. Each regional grid 4020 is defined based on the city grid origin 4010 by placing a grid centered at the origin 4010 with a false easting, e.g., along a X axis, and northing, e.g., along a Y axis.

The grid cells 4030 are identified by an easting cell designator, e.g., X axis coordinate, paired with a northing cell designator, e.g., Y axis coordinate, with successive pairs of designators defining grid cells of increasing precision. For each pair, the easting cell designator is always first and the northing cell designator is always second. The cell designators range between 0-9. The false easting and northing puts division between 4 and 5 along the X axis and Y axis at the grid origin.

The first pair of designators in a hierarchical grid address or ULA for a geographical location represent a specific 10 km×10 km cell 4030. For example, in the ULA “US.CA.SA.78.21”, the “78” indicates that a geographical location 4040 is in cell number “78”, i.e., 7 along the X axis or east direction and 8 along the Y axis or north direction, in the 100 km×100 km regional grid 4020.

With reference to FIG. 23, each cell 4030 may be further divided into a 10 sub-cell×10 sub-cell grid 4050 (100 grid rectangles or sub-cells), where each grid sub-cell 4060 is 1 km×1 km. The grid 4050 may be referred to as a cell grid because the grid 4050 represents a specific 10 km×10 km cell 4030 of the regional grid 4020. The second pair of designators in a hierarchical grid address or ULA for a geographical location represent a specific 1 km×1 km sub-cell 4060 in the cell grid 4050. For example, in the ULA “US.CA.SA.78.21”, the “21” indicates that the geographical location 4040 is in sub-cell number “21”, i.e., 2 along the X axis or east direction and 1 along the Y axis or north direction, in the 10 km×10 km cell grid 4050.

Next lower levels of pair designators in a hierarchical grid address or ULA for a geographical location are determined in a similar manner to that described above with respect to FIGS. 22 and 23, dividing each higher level cell into a 10 sub-cell×10 sub-cell lower level grid (100 cells), up to the desired level of precision or resolution for the hierarchical grid address or ULA. For example, for the ULA “US.CA.SA.78.21.01.61.37”, “01” indicates that the appropriate 100×100 meter cell is begins at easting “0” and northing “1”. The 10×10 meter cell is begins at easting “6” and northing “1”. Finally, the 1×1 meter cell is begins at easting “3” and northing “7”.

With reference specifically to FIG. 24, a preferred embodiment of a nested grid structure 4100 of a geographic referencing system and method of creating the same will now be described in more detail. A number of smaller, local cities such as city 4120 may exist partially or entirely within the geographical area represented by a regional grid 4020 of a larger city or population area 4025. The local city 4120 may be, for example, the city of Irvine, Calif., and the larger city 4025 that the regional grid 4020 is centered on may be, for example, Santa Ana, Calif.

For each local city (or some of the more major local cities) within the regional grid 4020, a reference point or local city grid origin 4130 may be chosen for the city 4120. The local city grid origin 4130 has a known address within a global referencing system such as the World Geodetic System (WGS). The local city grid origin 4130 is preferably positioned at the ten minute of latitude and ten minute of longitude intersection nearest the city center or city centroid for the local city 4120.

Similar to the regional grid 4020, a local city grid 4140 is preferably a 10 cell×10 cell grid (100 grid rectangles or cells), where each grid cell 4145 is 10 km×10 km. Thus, the local city grid 4140 preferably also covers a 100 km×100 km area. The local city grid 4140 is preferably positioned so that the local city origin 4130 resides in cell number “55” of the local city grid 4140, cell number “55” of the local city grid 4140 coincides with the cell 4030 of the regional grid 4020 that the local city origin 4130 resides in, e.g., cell number “11” of the regional grid 4020, and so that the cells 4145 of any portion of the local city grid 4140 that overlap with the regional grid 4020 coincide with the cells 4030 of the regional grid 4020. Having the cells 4145 of the local city grid 4140 coincide with the cells 4030 of the regional grid 4020 creates the nesting grid structure 4100.

As a result of the nesting grid structure 4100, a geographical location such as a Point of Interest (“POI”) 4160 in a local city 4120, e.g., Irvine, Calif., may be identified with an hierarchical address, e.g., ULA, with respect to the regional grid 4020, e.g., US.CA.SA.22, and/or the local city grid 4140, e.g., US.CA.IRV.66. Because the grids 4140, 4020 are nested so that the cells from overlapping portions directly coincide, e.g., cell number “22” of the regional grid 4020 is the same as cell number “66” of the local city grid 4140. Accordingly, the lower levels of pair designators in such an hierarchical address would be the same, e.g., US.CA.SA.22.33.01.02 versus US.CA.IRV.66.33.01.02.

It should be noted, because each local city grid 4140 is a 10 cell×10 cell grid representing a 100 km×100 km area, a geographical location such as a POI 4170 located outside of the local city 4120, but within one of the cells 4145 of the local city grid 4140, may be identified with respect to the local city grid 4140. For example POI 4170, which is located outside of the local city 4120, e.g., Irvine, but in cell number “48” of the local city for city 4120, grid 4140 and congruent cell number “04” of the regional grid 4020 may have the following respective ULAs: US.CA.IRV.48.05.01.02 and US.CA.SA.04.05.01.02. Similarly, a geographical location such as POI 4180 that is outside of the regional grid 4020, outside of the local city 4120, and inside the local city grid 4140 (cell number “81”), may have a ULA such as US.CA.IRV.81.75.01.02. Being able to refer to a location relative to several grids is advantageous because persons or businesses may want to determine their location and/or navigate in and around an area with reference to different cities. Persons or businesses may believe that they are “functionally” located within the “sphere of influence” of a specific location although they may not be physically close. For example, a person who lives and works in the city of Irvine, Calif. may want to navigate in and around the area of Irvine, Calif. and one or more adjacent cities or unincorporated areas with reference to Irvine, Calif., while at the same time a person who lives and works in the adjacent city of Tustin, Calif. may want to navigate in and around the exact same area with reference to Tustin, Calif.

Although FIG. 24 illustrates a single local city grid 4140 nested with a single regional grid 4020, preferably multiple local city grids 4140 are nested with each other and with multiple regional grids 4020. Thus, as a geographical location may be identified with a different ULA with respect to a regional grid 4020 and with respect to a local city grid 4140, a geographical location may have even more ULAs if the geographical location falls within overlapping regional grids and/or local city grids.

Regional grid information and local grid information may be stored in the grid definition file(s) 109 (FIG. 5) described above. The regional grid information and local grid information preferably includes all the parameters necessary to define the grids 4020, 4140. Such information includes the lat/lon coordinates of the reference point or origin of the grid, the dimensions of the grid, and the rotation and scaling of the grid cells, although the nesting grid structure will typically require uniform dimensions, rotation and scaling of grid cells. The grid definition file(s) 109 and grid algorithms may be stored on the navigational device/portable computing device or one or more of the servers described above. Thus, all the information needed to convert between a grid address within the grid and lat/lon coordinates is provided.

With reference to FIG. 25, a preferred embodiment of a method of addressing a geographical location using the local city grids 4140 of the nested grid structure 4100 will now be described. The method of addressing may be carried out by, for example, but not by way of limitation, the navigation device/portable computer device and/or the one or more servers described above.

At step 4200, a geographical location is provided. This may include, for example, but not by way of limitation, providing the global coordinates, e.g., lat/lon, of the location of the navigation device/portable-computing device using a GPS receiver (or other automatic location identification device), providing the global coordinates of a POI by manually entering coordinates into the navigation device/portable-computing device, and providing the global coordinates of a POI to the navigation device/portable computer device and/or the one or more servers automatically as a result of a query, e.g., query for gas stations.

Next, at step 4210, a local city grid 4140 corresponding to the geographical location provided is determined. The local city grid 4140 has a plurality of grid cells 4145, a reference point or local city grid origin 4130, global coordinates of the reference point defined in accordance with a known global latitude—longitude coordinate system based on a know geodetic datum, such as, but not by way of limitation, the WGS-84 system, and a local city grid name appended to hierarchically arranged names or abbreviations for other political subdivisions, e.g., US.CA.IRV for the Country of the United States, the state of California, and the city of Irvine. The local city grid 4140 corresponding to the geographical location may be determined by searching for the local city grid 4140 with a local city grid origin 4130 closest to the geographical location. For example, a query for the lat/lon coordinates of the origins 4130 of the local city grids 4140 closest to the lat/lon coordinates of a POI may be used to determine the local city grid 4140 encompassing the POI.

At step 4220, a cell 4145 of the local city grid 4140 corresponding to the geographical location is subdivided into as many levels of hierarchically-arranged sub-cells as necessary to obtain a desired addressing precision.

At step 4230, each sub-cell is associated with a sub-cell code or pair of designators.

At step 4240, each sub-cell is identified with a hierarchical arrangement of codes or pairs of designators.

At step 4250, the geographical location is addressed with an address formed by appending to the name of the local city grid a hierarchical arrangement of codes corresponding to the geographical location.

With reference to FIG. 26, a preferred embodiment of a method of addressing a geographical location within overlapping geographical areas of a local city grid 4140 and regional grid 4020 of a nested grid structure 4100 will now be described. The method of addressing may be carried out by, for example, but not by way of limitation, the navigation device/portable computer device and/or the one or more servers described above.

At step 4300, a first address of a geographical location in a first geographical area is provided. The address includes a hierarchical arrangement of codes of a first pre-defined grid corresponding to the first geographical area appended to a name of the first grid. The first pre-defined grid may be a local city grid 4140 or a regional grid 4020. Thus, the first address may be regional grid address or a local city address. The first address of a geographical location may be determined by a process such as that described above with respect to FIG. 25 for addressing a geographical location with respect to a local city grid or a similar process for addressing a geographical location with respect to a regional grid.

At step 4310, a second pre-defined grid which corresponds to a second geographical area is determined. The second geographical area has a portion which overlaps at least in part with the first geographical area, and the geographical location being within the overlapping portion. The second pre-defined grid is a local city grid 4140 or a regional grid 4020, and is the opposite type of grid from that of the first pre-defined grid. The second pre-defined grid may be determined by searching for reference points or origins of grids (of a type opposite to that of the first pre-defined grid) closest to the geographical location. For example, if the first pre-defined grid is a local city grid 4140, a query of the lat/lon coordinates of the origins 4010 of the regional grids 4020 closest to the lat/lon coordinates of the geographical location may be used to determine the regional grid 4020 encompassing the geographical location.

At step 4320, a hierarchical arrangement of codes of the second grid corresponding to the geographical location is determined.

At step 4330, the hierarchical arrangement of codes of the second grid corresponding to the geographical location is appended to the name of the second grid to form a second address of the geographical location.

The navigational device/portable-computing device described above may include a U/I module that allows the user to select between a “region lock” (or “district lock”) mode and a “city lock” mode. The “region lock” mode or similar mode may cause the navigational device/portable-computing device and/or one or more servers to utilize the district or regional centroids for address generation. In this mode, the ULAs and PLAs would be displayed and/or utilized with respect to districts or regions, e.g., US.CA.SA.04.05.01.02 or US.CA.SA.MACD. Thus, in a mode representative of a “region lock” mode, navigation, address generation, etc. would be done at a district or regional level.

The “city lock” mode or similar mode may cause the navigational device/portable-computing device and/or one or more servers to utilize specific local city grids, i.e., the method illustrated in FIG. 25, for address generation. In this mode, the ULAs and PLAs would be displayed and/or utilized with respect to local cities, e.g, US.CA.IRV.48.05.01.02 or US.CA.IRV.MACD. Thus, in a mode representative of a “city lock” mode, navigation, address generation, etc. would be done at a more local level.

In addition, the navigational device/portable-computing device described above may include a user interface (U/I) module that allows the user to easily view, scroll through or select specific district or city grids that may cover a specific area. One advantage of the nested grid structure is that changing the district or city grid reference between city grids that are nested with the same district grid will not change every reference in the ULA, but only the initial city grid reference and the initial 10 km×10 km cell associated with each different city grid.

In the “city lock” mode, when a user is identified as being within a local city 4120, the cells, e.g., cell numbers 44, 54, 64, 74, 45, 55, 65, 75, 46, 56, 66, of the local city grid 4120 that the local city resides within may be activated. For example, unless the user or a POI is indicated as being outside of the local city 4120, all further database queries, e.g., database query for commonly used terms such as “burgers,” “shopping,” “banks,” etc., performed by the navigation device/portable-computing device and/or one or more servers may be limited to establishments located in the geographical area defined by those cells, thus reducing the complexity of inputting future locational addresses.

Thus, nesting local city grids with the regional grids allows locations to be referenced with respect to more general, regional grids, and/or more localized, local city grids. ULAs and PLAs determined with reference to local city grids generally have more geographic meaning to users than ULAs and PLAs determined with reference to regional grids. Search speed is also improved by nesting local city grids with regional grids because of recursive decomposition (i.e., the nested structure allows you to directly target a geographic area for search by using regular indices).

With reference to FIG. 27, the nesting grid structure and method of creating and using the same, as well as the other aspects described in Section I-VI, may be implemented using hardware, software or a combination thereof and may be implemented in one or more computer systems or other processing systems. In fact, in one embodiment, the invention is directed toward one or more computer systems capable of carrying out the functionality described herein. An exemplary computer system 2201 includes one or more processors, such as processor 2204. The computer system 2201 includes one or more processors, such as processor 2204. The processor 2204 is connected to a communication bus 2202. Various software embodiments are described in terms of this example computer system. After reading this description, it will become apparent to a person skilled in the relevant art how to implement the invention using other computer systems and/or computer architectures.

Computer system 2202 also includes a main memory 2206, preferably random access memory (RAM), and can also include a secondary memory 2208. The secondary memory 2208 can include, for example, a hard disk drive 2210 and/or a removable storage drive 1012, representing a floppy disk drive, a magnetic tape drive, an optical disk drive, etc. The removable storage drive 2212 reads from and/or writes to a removable storage unit 2214 in a well-known manner. Removable storage unit 2214, represents a floppy disk, magnetic tape, optical disk, etc. which is read by and written to by removable storage drive 2212. As will be appreciated, the removable storage unit 2214 includes a computer usable storage medium having stored therein computer software and/or data.

In alternative embodiments, secondary memory 2208 may include other similar means for allowing computer programs or other instructions to be loaded into computer system 2201. Such means can include, for example, a removable storage unit 2222 and an interface 2220. Examples of such can include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as an EPROM, or PROM) and associated socket, and other removable storage units 2222 and interfaces 2220 which allow software and data to be transferred from the removable storage unit 2222 to computer system 2201.

Computer system 2201 can also include a communications interface 2224. Communications interface 2224 allows software and data to be transferred between computer system 2201 and external devices. Examples of communications interface 2224 can include a modem, a network interface (such as an Ethernet card), a communications port, a PCMCIA slot and card, etc. Software and data transferred via communications interface 2224 are in the form of signals which can be electronic, electromagnetic, optical or other signals capable of being received by communications interface 2224. These signals 2226 are provided to communications interface via a channel 2228. This channel 2228 carries signals 2226 and can be implemented using wire or cable, fiber optics, a phone line, a cellular phone link, an RF link and other communications channels.

In this document, the terms “computer program medium” and “computer usable medium” are used to generally refer to media such as removable storage device 2212, a hard disk installed in hard disk drive 2210, and signals 2226. These computer program products are means for providing software to computer system 2201.

Computer programs (also called computer control logic) are stored in main memory and/or secondary memory 2208. Computer programs can also be received via communications interface 2224. Such computer programs, when executed, enable the computer system 2201 to perform the features of the present invention as discussed herein. In particular, the computer programs, when executed, enable the processor 2204 to perform the features of the present invention. Accordingly, such computer programs represent controllers of the computer system 2201.

In an embodiment where the invention is implemented using software, the software may be stored in a computer program product and loaded into computer system 2201 using removable storage drive 2212, hard drive 2210 or communications interface 2224. The control logic (software), when executed by the processor 2204, causes the processor 2204 to perform the functions of the invention as described herein.

In another embodiment, the invention is implemented primarily in hardware using, for example, hardware components such as application specific integrated circuits (ASICs). Implementation of the hardware state machine so as to perform the functions described herein will be apparent to persons skilled in the relevant art(s).

In yet another embodiment, the invention is implemented using a combination of both hardware and software.

While embodiments and applications of this invention have been shown and described, it would be apparent to those in the field that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the appended claims. 

What is claimed is:
 1. A nested grid structure of a geographical referencing system, comprising: one or more regional grids generally centered on one or more respective grid origins, each regional grid including a plurality of cells, one or more local cities located at least partially within said one or more regional grids; one or more local city grids, each local city grid including a plurality of cells, said one or more local city grids generally centered on one or more respective local city origins of said one or more local cities and at least some of the plurality of cells of said one or more local city grids directly overlap and coincide with at least some of the plurality of cells of said one or more regional grids to form a nested grid structure.
 2. The nested grid structure of claim 1, wherein said one or more regional grids and said one or more local city grids are 10 cell×10 cell and 100 km×100 km.
 3. The nested grid structure of claim 1, wherein said one or more regional grids and said one or more local city grids include cells numbered from 0-9 from left-to-right along an X-axis and 0-9 from bottom-to-top along a Y-axis.
 4. The nested grid structure of claim 3, wherein said one or more local city grids are centered so that said local city origin resides within a cell corresponding to “5” along the X-axis and “5” along the Y-axis.
 5. The nested grid structure of claim 1, wherein said local city grid origin is located at a predetermined level of latitude and longitude intersection nearest a city center of the local city.
 6. The nested grid structure of claim 1, wherein said local city grid origin is located at a ten minute of latitude and a ten minute of longitude intersection nearest a city center of the local city.
 7. A method of creating a nested grid structure for a geographical referencing system, comprising: determining a regional origin for a region; centering a regional grid for said region generally on said regional origin, said regional grid including a plurality of cells; determining a local city origin for a local city located at least partially within said regional grid; positioning a local city grid including a plurality of cells so that the local city grid is generally centered on said local city origin and at least some of the plurality of cells of said local city grid directly overlap and coincide with at least some of the plurality of cells of said regional grid to form a nested grid structure.
 8. The method of claim 7, wherein said regional grid and said local city grid are 10 cell×10 cell and 100 km×100 km grids.
 9. The method of claim 7, wherein said grids include cells numbered from 0-9 from left-to-right along an X-axis and 0-9 from bottom-to-top along a Y-axis.
 10. The method of claim 9, wherein positioning said local city grid includes generally centering said local city grid so that said local city origin resides within a cell corresponding to “5” along the X-axis and “5” along the Y-axis.
 11. The method of claim 7, wherein said local city grid origin is located at a predetermined level of latitude and longitude intersection nearest a city center of the local city.
 12. The method of claim 7, wherein said local city grid origin is located at a ten minute of latitude and a ten minute of longitude intersection nearest a city center of the local city.
 13. A method of addressing a geographical location using a local city grid, comprising: providing a geographical location; determining a local city grid corresponding to the geographical location, the local city grid having a plurality of grid cells, a local city grid origin having global coordinates defined in accordance with a known global referencing system, and a local city grid name; subdividing a cell corresponding to the geographical location into as many levels of hierarchically arranged sub-cells as necessary to obtain a desired addressing precision; associating each sub-cell with a sub-cell code; identifying each sub-cell with a hierarchical arrangement of codes; addressing the geographical location with an address formed by appending to the name of the local city grid a hierarchical arrangement of codes corresponding to the geographical location.
 14. The method of claim 13, wherein determining a local city grid corresponding to the geographical location includes determining a local city grid with a local city grid origin closest to the geographical location.
 15. The method of claim 13, wherein the local city grid name includes top, second, and third level hierarchical codes for identifying countries, states/provinces, and local cities.
 16. The method of claim 15, wherein the third level hierarchical code for a local city is a two or three alpha character mnemonic.
 17. The method of claim 13, wherein the local city grid is nested with a regional grid.
 18. A method of addressing a geographical location within overlapping geographical areas of a regional grid and a local city grid of a geographical referencing system, comprising: providing a first address of a geographical location in a first geographical area, the first address comprising a hierarchical arrangement of codes of a first pre-defined grid corresponding to the first geographical area appended to the name of the first grid, the first grid being either a regional grid or a local city grid; determining a second pre-defined grid which corresponds to a second geographical area, the second geographical area having a portion which overlaps at least in part the first geographical area, the geographical location being within the overlapping portion, the second pre-defined grid being the opposite of the first predefined grid, either a regional grid or a local city grid; determining a hierarchical arrangement of codes of the second grid corresponding to the geographical location; appending the hierarchical arrangement of codes of the second grid corresponding to the geographical location to the name of the second grid to form a second address of the geographical location.
 19. The method of claim 18, wherein providing a first address of a geographical location includes: determining a first pre-defined grid corresponding to the geographical location, the first pre-defined grid having a plurality of grid cells, a first pre-defined grid origin having global coordinates defined in accordance with a known global referencing system, and a first pre-defined grid name; subdividing a cell corresponding to the geographical location into as many levels of hierarchically arranged sub-cells as necessary to obtain a desired addressing precision; associating each sub-cell with a sub-cell code; identifying each sub-cell with a hierarchical arrangement of codes; addressing the geographical location with an address formed by appending to the name of the first pre-defined grid a hierarchical arrangement of codes corresponding to the geographical location.
 20. The method of claim 18, wherein determining a second pre-defined grid includes determining a second pre-defined grid with a grid origin closest to the geographical location.
 21. A method of addressing a geographical location using a nested grid structure of a geographic referencing system, the nested grid structure including one or more local city grids nested with one or more regional grids, comprising: providing a geographic location; determining a grid which corresponds to the geographical location, the grid including at least one of said one or more local city grids and said one or more regional grids; determining a hierarchical arrangement of codes of the grid corresponding to the geographical location; appending the hierarchical arrangement of codes of the grid corresponding to the geographical location to the name of the grid to form an address of the geographical location.
 22. The method of claim 21, further including selecting a mode representative of a local city address generation mode or a regional address generation mode.
 23. The method of claim 22, wherein the type of grid determined to correspond to the geographical location and address generated depends on the mode selected. 